Modelling of the Creep Behavior of FRP-Confined Short Concrete Columns Under Compressive Loading

Creep in concrete is a complex phenomenon in which many physical and chemical parameters are involved. In this material, not only intrinsic properties can affect the creep behaviour but also external effects such as: humidity and applied stress. When concrete is confined with FRP materials the investigation on its creep behaviour becomes more crucial. An experimental program conducted in the laboratory of the civil engineering department of the University of Sherbrooke attempts to clarify ambiguities of the creep performance of CFRP confined columns. Ongoing investigation shows the promising results expected from the application of CFRP wrapping to circular concrete columns. The main parameters under study are the level of sustained load and the confinement ratio. In the L2MS laboratory, Berthet et al. developed an analytical model to evaluate the ultimate capacity and the stress-strain behaviour of the confined concrete as a function of each material parameter. On the basis of the experimental results obtained by Thériault et al. on the creep performance of such cylinders the model is modified in order to take into account the rheological behaviour of concrete confined with CFRP.     

The Shortening of MWNT‐SPION Hybrids by Steam Treatment Improves Their Magnetic Resonance Imaging Properties In Vitro and In Vivo

Carbon nanotubes (CNTs) have been advocated as promising nanocarriers in the biomedical field. Their high surface area and needle‐like shape make these systems especially attractive for diagnostic and therapeutic applications. Biocompatibility, cell internalization, biodistribution, and pharmacokinetic profile have all been reported to be length dependent. In this study, further insights are gotten on the role that the length of CNTs plays when developing novel contrast agents for magnetic resonance imaging (MRI). Two samples of CNTs with different length distribution have been decorated with radio‐labeled iron oxide nanoparticles. Despite characterization of the prepared hybrids reveals a similar degree of loading and size of the nanoparticles for both samples, the use of short CNTs is found to enhance the MRI properties of the developed contrast agents both in vitro and in vivo compared to their long counterparts.     

Methods of Observing and Correcting Errors in Data-Acquisition Storage and Transmission Systems

Data protection methods are compared for measurements systems, which are based on the use of error-correcting codes, which can correct errors of given multiplicity and observe the maximum number of uncorrectable errors.Translated from Izmeritel’naya Tekhnika, No. 3, pp. 3–6, March, 2005.     

Efficient finite element formulation for geothermal heating systems. Part I: steady state

This paper presents the development of a computationally efficient finite element tool for the analysis of 3D steady state heat flow in geothermal heating systems. Emphasis is placed on the development of finite elements for vertical borehole heat exchangers and the surrounding soil layers. Three factors have contributed to the computational efficiency: the proposed mathematical model for the heat exchanger, the discretization of the spatial domain using the Petrov–Galerkin method and the sequential numerical algorithm for solving the resulting system of non‐linear equations. These have contributed in reducing significantly the required number of finite elements necessary for describing the involved systems. Details of the mathematical derivations and some numerical examples are presented. Copyright © 2005 John Wiley & Sons, Ltd.     

Increasing photoactivity of titanium dioxide immobilized on glass plate with optimization of heat attachment method parameters

In the present work the optimization of heat attachment method for increasing photoactivity of immobilized TiO₂ on glass plate was investigated. Results show that sonication time, TiO₂ suspension dosage, immobilization temperature, solvent type and immobilization replications are very effective on the photoactivity of immobilized TiO₂ on glass plate on the removal of C.I. Acid Red 88 (AR88) and optimizing these parameters increases the photoactivity of immobilized catalyst. In other step, the effect of operational parameters such as light intensity and initial concentration of AR88 on the removal of AR88 was investigated with four times immobilized TiO₂ on glass plate. Results show that removal rate decreases with increasing initial concentration of AR88 but increases with increasing UV-light intensity.     

Numerical analysis of a SWEAT structure with an improved one dimensional nonlinear model

An improved one dimensional (1 − D) nonlinear model of the thermal response of the Standard Wafer-level Electromigration Accelerated Test (SWEAT) structure is described. The major improvement in this model are accurate predictions of the critical current density j_o; according to older models j_o is inversely proportional to the “power” I²R/R(T_s), while our model shows a different (increasing) trend and is confirmed by measurements. The ratio of the maximum temperature increase to the average temperature increase (γ) for the investigated structure depends on the relative change of the resistance and normalized current , and can be calculated within 1% from basic material and structure parameters. The model includes the edge correction factor α depending on the geometry of the structure (W_n/t_i), material parameters and stress current I. Using the corrected values for the edge correction factor, the maximum temperature increase in the SWEAT test structure can be calculated within less than 5°C.     

Semi conducting properties amd microstructure of x%V2O5·(100−x)% (As2O3·B203) glasses

Binary semiconducting glasses of the x%V₂O₅·(100?x)%(As₂O₃· B₂O₃) system with x ranging from 50 to 70 mol% have been investigated to elucidate their electronic conduction and microstructure. The values of conductivity and activation energy obtained for these glasses are in agreement with previous results on most V₂O₅-based glasses. Arguments for a small-polaron conduction of nonadiabatic type are presented. All the samples show a glass-glass type phase separation.     

Acquiring reusable skills in intrinsically motivated reinforcement learning

Journal of Intelligent Manufacturing - This paper proposes a novel incremental model for acquiring skills and using them in Intrinsically Motivated Reinforcement Learning (IMRL). In this model, the...     

Target-shooting exergame with a hand gesture control

Exertion games (exergames) pose interesting challenges in terms of user interaction techniques. Players are commonly unable to use traditional input devices such as mouse and keyboard, given the body movement requirements of this type of videogames. In this work we propose a hand gesture interface to direct actions in a target-shooting exertion game that is played while exercising on an ergo-bike. A vision-based hand gesture interface for interacting with objects in a 3D videogame is designed and implemented. The system is capable to issue game commands to any computer game that normally responds to mouse and keyboard without modifying the underlying source code of the game. The vision system combines Bag-of-features and Support Vector Machine (SVM) to achieve user-independent and real-time hand gesture recognition. In particular, a Finite State Machine (FSM) is used to build the grammar that generates gesture commands for the game. We carried out a user study to gather feedback from participants, and our preliminary results show the high level of interest from users use this multimedia system that implements a natural way of interaction. Albeit some concerns in terms of comfort, users had a positive experience using our exertion game and they expressed their positive intention to use a system like this in their daily lives.